A reciprocating motor has a plane form of magnetic flux compared to a general motor which has a steric structure of magnetic flux. In the reciprocating motor, a magnet paddle disposed between an outer stator and an inner stator is linearly moved according to variation of the magnetic flux.
As shown in FIGS. 1 and 2, a reciprocating motor according to the conventional art, includes an outer stator 10 having a cylindrical shape by radially stacking a plurality of lamination sheets 12 at an outside of a bobbin 60 in which a winding coil 50 is wound; an inner stator 20 having a cylindrical shape by radially stacking a plurality of lamination sheets 22, and disposed in an inner circumference of the outer stator 10 at a certain air gap from an inner circumferential surface of the outer stator 10; and a cylindrical magnet paddle 40 disposed between the outer stator 10 and the inner stator 20, and having a plurality of magnets 30 installed in a circumferential direction of thereof.
A terminal part 70 for applying an external power to the winding coil 50 inside the bobbin 60 is protruded at one side of the bobbin 60, and a plurality of lamination sheets 12 are uniformly stacked in the vicinity of the terminal part 70.
Operations of the conventional reciprocating motor constructed as above will now be described. When power is applied to a winding coil 50 of the outer stator 10, flux is formed around the winding coil 50. The flux flows to form a closed loop through the outer stator 10 and the inner stator 20. According to this, the magnet paddle 40 is pushed or pulled according to the direction of the flux, and thus is linearly and reciprocally moved.
In the conventional reciprocating motor as above, the terminal part 70 for connecting external power to the winding coil 50 is installed between the lamination sheets 12 of the outer stator 10, and the lamination sheets 12 are not stacked as much as the width of the terminal part 70. For this reason, an electromagnetic force generated in the vicinity of the terminal part 70 is relatively smaller than an electromagnetic force generated at the opposite side of the terminal part 70. Therefore, an electromagnetic field formed between the outer stator 10 and the inner stator 20 is not uniform, the electromagnetic field is eccentrically formed toward the opposite side of the terminal part 70.
By this eccentricity of the electromagnetic field, the magnet paddle 40 is moved toward the opposite side of the terminal part 70, that is, in an arrow direction in FIGS. 3 and 4. Therefore, the cylindrical magnet paddle 40 collides with the outer stator 10, and thus friction is caused by the eccentric motion of the magnet paddle 40.